1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) panel, and more particularly to, a dispenser for an LCD panel and a dispensing method using the same. Although the present invention is suitable for a wide scope of applications, it is particularly suitable for reducing a time taken to form seal patterns on a plurality of liquid crystal display panels formed on a large size mother substrate, and forming seal patterns on small-sized LCD panels formed on a large size mother substrate.
2. Discussion of the Related Art
In general, an LCD device is a display device for displaying an image by controlling light transmittance of pixels arranged in a matrix shape and then individually supplying data signals based on image information to the pixels. Therefore, the LCD device includes an LCD panel on which the pixels are arranged in the matrix shape, a gate driving unit, and a data driving unit for driving the pixels.
The LCD panel includes a color filter substrate and a thin film transistor array substrate attached with a predetermined cell-gap, and a liquid crystal layer formed at the cell-gap between the color filter substrate and the thin film transistor array substrate. A plurality of data lines for transmitting data signals from the data driving unit to the pixels, and a plurality of gate lines for transmitting scan signals from the gate driving unit to the pixels are orthogonal to each other on the LCD panel. The pixels are defined in each of the intersections of the data lines and the gate lines. Thin film transistors for switching the data signals transmitted from the data driving unit through the data lines, and pixel electrodes for receiving the data signals through the thin film transistors are individually formed in the pixels. The gate driving unit sequentially supplies the scan signals to the plurality of gate lines, thereby sequentially selecting one line of the pixels arranged in the matrix shape. The data driving unit supplies the data signals to the selected pixels.
Common electrodes and pixel electrodes are formed on the LCD panel on which the color filter substrate and the thin film transistor array substrate are attached, for applying an electric field to the liquid crystal layer. When a voltage is applied to the common electrodes, if a voltage of the data signals applied to the pixel electrodes is controlled, the liquid crystals of the liquid crystal layer are rotated due to dielectric anisotropy by the electric field between the common electrodes and the pixel electrodes, for transmitting or intercepting light in each pixel to display characters or images.
A related art LCD device will now be explained in detail with reference to FIG. 1. FIG. 1 is a schematic plane diagram illustrating a unit LCD panel on which a thin film transistor array substrate and a color filter substrate are attached to face each other in the related art LCD device.
Referring to FIG. 1, the LCD panel 100 includes an image display unit 113 on which liquid crystal cells are arranged in a matrix shape, a gate pad unit 114 connected to gate lines of the image display unit 113, and a data pad unit 115 connected to data lines of the image display unit 113. The image display unit 113 includes a thin film transistor array substrate 113 and a color filter substrate 102. Herein, the gate pad unit 114 and the data pad unit 115 are formed at the edges of the thin film transistor array substrate 101 that does not overlap the color filter substrate 102. The gate pad unit 114 supplies scan signals from a gate driver integration circuit to the gate lines, and the data pad unit 115 supplies image information from a data driver integration circuit to the data lines. In addition, the data lines receiving the image information and the gate lines receiving the scan signals are arranged on the thin film transistor array substrate 101 to vertically cross each other. Thin film transistors for switching the liquid crystal cells, and pixel electrodes connected to the thin film transistors for driving the liquid crystal cells are formed in the intersections of the data lines and the gate lines, respectively. A protecting film is formed on the entire surface to protect the electrodes and the thin film transistors.
Color filters separated by cell regions by a black matrix and common transparent electrodes are formed on the color filter substrate 102. The common transparent electrodes are counter electrodes to the pixel electrodes formed on the thin film transistor array substrate 101. A cell-gap is formed between the thin film transistor array substrate 101 and the color filter substrate 102 to isolate the two substrates from each other by spacers. The thin film transistor array substrate 101 and the color filter substrate 102 are attached by a seal pattern 116 formed at a peripheral region of the image display unit 113, thereby forming the unit LCD panel.
A method for simultaneously forming a plurality of unit LCD panels on a large size mother substrate has been generally employed to improve yield of the LCD panels. A process is required to separate the unit LCD panels from the large size mother substrate by cutting and polishing the mother substrate. A liquid crystal layer may be formed at the cell-gap by injecting a liquid crystal material into the unit LCD panel via a liquid crystal injection hole, and then the liquid crystal injection hole is sealed up. Accordingly, the unit LCD panels are fabricated by the processes for individually fabricating the thin film transistor array substrate 101 and the color filter substrate 102, soldiering the thin film transistor array substrate 101 and the color filter substrate 102 with a predetermined cell-gap, cutting the attached structure into the unit LCD panels, and injecting liquid crystal into the unit LCD panels.
Especially, a process for forming the seal pattern 116 at the peripheral region of the image display unit 113 is required so that the thin film transistor array substrate 101 and the color filter substrate 102 can be bonded together. A related art method for forming seal patterns will now be explained with reference to FIGS. 2A and 2B. FIGS. 2A and 2B are exemplary diagrams illustrating a screen printing method for forming the seal patterns.
As illustrated in FIGS. 2A and 2B, the screen printing method requires a screen mask 206 patterned to selectively expose formation regions of a plurality of seal patterns 216A-216F, and a squeegee 208 for simultaneously forming the plurality of seal patterns 216A-216F by selectively supplying a sealant 203 to a substrate 200 through the screen mask 206. The plurality of seal patterns 216A-216F formed on the substrate 200 generate gaps for forming liquid crystal layers and prevent the liquid crystal material from leaking out of image display units 213A-213F. Accordingly, the plurality of seal patterns 216A-216F are formed at the peripheral regions of the image display units 213A-213F of the substrate 200 with liquid crystal injection holes 204A-204F at their one-side portions.
As shown in FIG. 2B, the screen printing method includes a formation step for forming the plurality of seal patterns 216A-216F on the substrate 200 by coating the sealant 203 on the screen mask 206 patterned with the formation regions of the plurality of seal patterns 216A-216F, and printing the coated sealant 203 by using the squeegee 208, and a drying step for leveling the resulting structure by evaporating solvents contained in the plurality of seal patterns 216A-216F.
Although the screen printing method has been generally employed because it has the simple processes, the screen printing method forms the plurality of seal patterns 216A-216F at the same time by coating the sealant 203 on the whole surface of the screen mask 206 and printing the coated sealant 203 by using the squeegee 208, thereby increasing the consumption amount of the sealant 203. Moreover, since the screen mask 206 contacts the substrate 200, rubbing defects occur on an orientation film (not shown) formed on the substrate 200, thereby reducing image quality of the LCD device.
A seal dispensing method has been proposed to solve the above problems of the screen printing method. FIG. 3 is an exemplary diagram illustrating the seal dispensing method for forming seal patterns. As shown in FIG. 3, a plurality of seal patterns 316A-316F are formed at peripheral regions of image display units 313A-313F on a substrate 300, such that a table 310 on which the substrate 300 is loaded is transferred in the long side and short side directions of the substrate 300, and a predetermined pressure is applied to a plurality of syringes 301A-301C fixedly aligned on a support member 314 to discharge a sealant. Herein, the seal patterns 316A-316F are sequentially formed in row units of the image display units 313A-313F.
The seal dispensing method selectively supplies the sealant to the formation regions of the seal patterns 316A-316F, thereby reducing the consumption amount of the sealant. Since the syringes 301A-301C do not contact the image display units 313A-313F, rubbing defects do not occur on an orientation film (not shown), thereby improving the image quality of the LCD device.
The seal dispensing method forms the seal patterns 316A-316F at the peripheral regions of the image display units 313A-313F of the substrate 300, by fixing the support member 314 on which the syringes 301A-301C are fixedly aligned, horizontally transferring the table 310 in the long side and short side directions of the substrate 300, and applying a predetermined pressure to the syringes 301A-301C filled with the sealant. However, a related art dispenser for an LCD panel for forming seal patterns and a dispensing method using the same have the following disadvantages.
First, since a size of an LCD panel increases, a size of a substrate for forming the large size LCD panel also increases. When a table is horizontally transferred in the long side and short side directions of the large size substrate to form seal patterns on the substrate, a driving space of the table must be increased twice in the long side and short side directions of the substrate. Therefore, if the area of the substrate increases twice, the space of the dispenser must be increased four times to obtain the driving space of the table, thereby reducing clean-room using efficiency.
Second, since the table on which the large size substrate is loaded is horizontally transferred in the long side and short side directions of the substrate, an extended period of time is taken to form the seal patterns, thereby resulting in low productivity.
Third, the related art dispenser for the LCD panel and the dispensing method using the same cannot form seal patterns on small-sized LCD panels. That is, in the case of the small-sized LCD panels, seal patterns cannot be formed at peripheral regions of image display units due to interferences between neighboring syringes.